As I’m sure you all know, I am passionate about healthy, balanced eating and I’m always finding tasty, nutritious ideas for meals and snacks. The area that I feel most strongly about however, is sugar. I’m all for moderation and I’m happy to enjoy the occasional sugary treat, but I cut refined sugar from my diet a couple of years ago and since then I’ve also cut down on fruit; instead I prioritise their less sugary cousin, vegetables. I didn’t properly understand why sugar is so bad for us or what happens when we consume it until I started to explore the science behind it, so I thought I’d share this information for anyone who’s also curious to know more.
I’ve written this (very) detailed post explaining what happens when we eat sugar, particularly in excess. As I have no qualifications (as of yet!) I have researched this topic thoroughly and included some important facts and references from several reliable sources, which I have listed for you in the bibliography at the bottom of this post. If you would like to know more, then I would recommend reading or watching any of the sources that I’ve mentioned.
I’ve put a lot of time and effort into this post which is why it’s so long – it’s more of an essay or article than a blog post! I have included a lot of scientific research and plenty of facts and figures to help you get stuck in. I hope you enjoy it as much as I enjoyed writing it and please feel free to share your own thoughts below.
The fact that obesity and related health issues are a universally growing problem won’t come as a shock, but the fact that we may have got the cause wrong might do. For years, it’s been thought that fat is the main reason for increasing obesity rates and heart attacks, but now it seems that a new culprit has been identified: sugar.
- The research:
Fat was made the scapegoat for the obesity crisis following a study by Ancel Keys. He associated rates of heart disease in seven countries with different dietary fat intakes and, showing the clear correlations which he’d found, concluded that increasing dietary fat levels resulted in an increasing risk of a heart attack. However he had actually looked at 22 countries and his correlations were not all convincing; Keys chose to include only those which supported his hypothesis.1 Neglecting to include these important details in his results, his findings made the headlines and fat became the enemy.
In the 1950s the UK’s leading nutritionist, John Yudkin, studied the data on heart disease and recognised a correlation with the consumption of sugar rather than fat. He conducted several experiments on animals and humans and realised that sugar is processed in the liver, where it’s converted to fat before entering the bloodstream. He also considered the fact that refined sugar had been part of western diets for just 300 years, whereas saturated fats have always been a part of our diet; for example they’re present in breast milk. It seemed more likely to be the recent addition to our diet, rather than the ‘prehistoric component’, which was making us sick.5 However, Yudkin’s findings were overshadowed by Keys’, which seemed to make more sense – the idea that fat makes you fat seemed obvious. As a result, Yudkin’s findings were forgotten. Now they have resurfaced.
- What is sugar and what happens when we consume it?
In order to understand why sugar needs to be limited, we need to understand what sugar is and look at what takes place in the body when we consume it. Sucrose, (table sugar), is a disaccharide made up of glucose and fructose.1 Refined or processed sugars provide ‘empty’ calories, meaning they give you energy but no nutrients. As a result they don’t fill you up and can lead to overeating, weight gain and an increased risk of contracting diseases.
The term ‘free sugars’ refers to any sugars added to food and drink, plus those found in honey and syrup, and also natural sugars found in fruit juices.3 When we consume free sugars, they are absorbed rapidly into our bloodstream, resulting in an energy boost and feelings of pleasure. Sugar causes the body to release the ‘happy hormone’ serotonin into the blood stream. The immediate ‘lift’ we get has led to us eating it to celebrate, to reward or to comfort ourselves. However, this ‘sugar rush’ triggers an increase in the amount of insulin released as the body tries to return blood glucose levels to normal. Our blood sugar levels spike and then drop (‘sugar crash’ or ‘slump’) leaving us feeling tired, craving more sugar and trapping us in a harmful cycle.4
Excessive sugar consumption can lead to an unhealthy gut and an array of nasty, even potentially fatal diseases. When you drink a large sugary drink or eat a large portion of refined carbohydrates, such as white pasta, very little chewing is necessary, so your body has no time to signal feelings of fullness. Most of this sugary load is absorbed by the small intestine, producing an unusual insulin response which changes the breakdown of glucose. This also causes the healthy gut microbes to be replaced by unhealthy species which feed on this sugar and multiply, upsetting the balance of bacteria in the gut. The microbes which expect to receive nutrients from the “food” receive only ‘empty calories’ and so send signals to the brain, instructing it to send more sugar. When this happens, the glucose is stored as fat, often as the internal (visceral) type.1 This increased fat storage can lead to problems like obesity, Type 2 Diabetes and a greater risk of liver disease and coronary heart disease.
- Too much of a good thing?
We do not need refined sugars or fructose in our diet, which is frequently consumed in the form of honey and fruit.1 But we do need glucose, which is found in wholegrains, fruit and vegetables. Addiction is encouraged by adding sugars to so much of our food and as our food becomes sweeter, our capacity for sweetness increases. Even fruit and vegetables are being bred to taste sweeter due to ‘customer demand’, reducing their nutrients and only encourages our sweet tooth.2
Another issue is the misconception that you can’t have too many natural sugars. Although fruit is nutritious and a good source of antioxidants, sugar is still sugar and consuming too much of it in any form is harmful. Furthermore, fructose, the sugar found in fruit, is the sweetest naturally occurring substance 1 and is extremely addictive.
Normally, food that is in the process of being digested causes the release of hormones in the gut lining, liver, pancreas and gall bladder that aid its breakdown. Simultaneously signals are sent to the brain to tell it that we’re full. The reason fructose is dangerous is because it interferes with appetite signals to the brain and alters the normal functioning of the hormones ghrelin, which signals hunger to the brain, and leptin, which produces a feeling of satiety, so you end up eating more than you need. 4
Fructose is converted directly to fat before entering the bloodstream.5 It’s better to eat whole fruit rather than drink fruit juice because the fibre in fruit (broken down by blending or juicing) slows the release of sugar into the bloodstream, preventing blood sugar spikes. This also occurs when fruit is consumed with protein or fat. Furthermore, many sports drinks contain fructose, which causes microbial fermentation, bloating and stomach cramps in increasing numbers of people.1 Therefore, just like other types of sugar, fructose should be limited.
- The guidelines on sugar consumption and unusual suspects:
The new recommendations from the World Health Organisation (WHO) are that only 5% of your daily calorie intake should consist of added or ‘free’ sugars. This is approximately five-six teaspoons (25g) for women and seven teaspoons (35g) for men. Yet some Brits are consuming as many as 40 teaspoons of sugar each day. 3 The main reasons for this are a lack of education and the fact that sugar is hidden in many food products, even ones which look deceptively healthy.6
The obvious examples include breakfast cereals and fizzy drinks. A 330ml can of Coca Cola contains 35g sugar, almost 9 teaspoons. Sugar is added to food like bread, ready-cooked meats and tinned products to help extend their shelf life.4 But it’s also found in some unexpected, seemingly healthy products. For example Sainsbury’s tomato and basil soup contains 15.9g (almost 4 teaspoons) of sugar (although some of this will be natural).
Another problem is that people pick low-fat options because they think they’re making the healthiest choice. However, low-fat products tend to have sugar added to them to improve the taste to make up for removal of fat.5 Full-fat products are actually beneficial because they are more filling than reduced-fat sugary alternatives, meaning you are less likely to overeat.
- The effect of sugar on our society and economy:
Because excessive consumption is having such a disastrous effect on our health, it’s also damaging our economy. There are 3.5 million people with Type 2 diabetes in the UK, costing the NHS £9 billion per year. There are also about 7000 low-limb amputations per year (about 130 per week) due to Type 2 diabetes which, unlike Type 1, is caused by lifestyle factors. Compare this to the fact that 13 years of British conflict in Iraq and Afghanistan resulted in only around 300 amputations, this is an incredibly worrying statistic. Diabetes already accounts for 10% of the NHS budget and in the case of Type 2 that’s around £8.8 billion.6 It places a huge strain on the NHS and services, which could be better used for unavoidable illnesses rather than those which can be prevented.
In Britain today 1 in 5 kids turn up to primary school at the age of 4 overweight or obese and 1 in 3 are overweight or obese when they leave at 11.6 These children are being set up for a life of ill health, which in turn will place a huge strain on the NHS as they are forced to deal with it.
Sugar also causes tooth decay. Bacteria in our mouths feast on the sugary foods we eat and produce lactic acid which make tiny holes in our dental enamel, resulting in tooth decay.1 It doesn’t matter how much you brush your teeth, if you’re constantly consuming sugar its effects will overwhelm any preventative measures. Every year 26,000 primary school-age kids go to hospital because of rotten teeth, and extracting them costs the NHS £30m a year. Sugar is the biggest reason for children going to hospital in England, so it makes sense that it’s now being likened to a ‘poison’ or ‘drug’.3 As with Type 2 diabetes, tooth decay can be prevented before it becomes an issue for the NHS to deal with.
- The solutions:
I think the best way of tackling the problem of excessive sugar consumption is by improving the quality of education on the topic. Schools should be educating children about the dangers of sugar and what a healthy, balanced diet and lifestyle look like. I think visualisation is a powerful way of teaching people, especially children. For example the ‘teaspoon rule’, whereby you divide the number of grams of sugar in a product by four to work out how many teaspoons of sugar a food product contains (for example 12g = 3 teaspoons), may help people to understand this better and might even deter some from consuming particularly sugary products. Cooking and nutrition should be made a compulsory part of the national curriculum, so everyone leaves school knowing how to produce healthy, balanced and cost-effective meals. Educating people enables them to make the right decisions, lead healthy lives, raise healthy children and reduce the strain on the NHS.
Jamie Oliver’s sugar tax is a good start; the money raised by Jamie’s in-restaurant sugar tax on fizzy drinks will fund food education for children and other plans to improve public health.3 However, we need to be doing more. Major food companies must stop adding unnecessary sugar to products where you wouldn’t expect to find sugar, because doing so may fuel profits, but also encourages addiction. We also need clearer labelling on foods that are high in sugar, so that people can make informed choices. However, education is key because knowing the sugar content of a product might not mean anything to some people unless they know its effect on their body and why they should be avoiding it.
Another way of reducing the severe impact of sugar on our bodies and on society would be to reduce the advertisement of unhealthy products. Children are exposed to a huge number of adverts displaying junk food, and adverts like those of Coca Cola, which display people having fun, dancing or playing sport while drinking Coca Cola, simply give children the wrong message. The TV programme Britain’s Got Talent is watched by 10 million people, more than 1 million of whom may be children, who can be exposed to over 11 unhealthy ads per hour.6
Sugar is an addictive and potentially toxic substance which is making us sicker and fatter, so we need to acknowledge this and put these solutions into action.
1 Spector, T., The Diet Myth (Great Britain: Weidenfeld & Nicolson, 2015), p.44, 149, 151, 160-1
2 New Scientist, ‘Bitter truth: How we’re making fruit and veg less healthy’
3 Oliver, J., ‘Jamie’s strategy to combat childhood obesity’
4 BBC iWonder, ‘Are there good and bad sugars?’
5 Leslie, I., ‘The Sugar Conspiracy’ The Guardian, (2016)
6 Oliver, J., ‘Jamie’s Sugar Rush’, documentary, Channel 4